Hi
Rear seat belts are attached to C pillar , but yes the seat belt holder for front seat passengers was part of the 10 stage fix on the DS , to re rivet them .
Anyway ...
New DS are supposedly fixed with respects to BPillar , but older vehicles are still susceptible.

Better of to search for oil dilution, early service, DPF faults to get some info ,the search on here is pretty good and you can ask questions on the relevant threads about these issues .

As above. I bought mine blind but with eyes wide open, and so far only the oil dilution and ticking b pillar remain unresolved.

Those issues aside, it's a fantastic and versatile vehicle, and if those issues were fixed for good then I would be keeping hold of it. Sadly, it would appear that they will never be fixed, so on that basis I will be bowing out in the next month or so and taking the financial hit on the chin. Shame really...